The Archaeological Museum of Nisyros is located on a central street in Mandraki, the capital of the island. It has numerous exhibits with high archaeological importance. Specifically, findings from the prehistoric site on the volcanic island of Yali, opposite Nisyros, are dated to the Final Neolithic Period of the 4th millennium BC. Excavations have revealed an intact Neolithic ellipsoid structure, residues of other buildings, and a cemetery.
Impressive are the rich finds from the necropolis of the ancient city, dating from the Archaic, Classical and Hellenistic Periods. There are also ceramic finds, mainly flat panels decorated with vivid written representations, which belong to a typical rhythm of the Eastern Dorida.
At the peak period of Nisyros in the 4th century BC, its extensive cemetery has brought to light not only large clay piths but also clay sarcophagi with abundant offerings, among which stand out red-clay pots, other clay pots and jewelry.
The museum also includes findings from the Early Christian, Byzantine and Post-Byzantine Nisyros, Early Christian column capitals of the 5th and 6th centuries AD. and depiction of the Byzantine iconostasis from the cathedral of Virgin Mary "Spiliani". It also features frescoes from the Byzantine churches of the island, surveillance material related to the major churches, knight castles and portable icons of post-Byzantine churches in Nisyros.